In the United States, approximately 10 million patients are operated on and anesthetized each year. While anesthetized, the patient's breathing functions are temporarily disabled. Ventilation is therefore supplied to the patient by the anesthesiologist during the procedure.
Ventilation is provided through an endotracheal tube. This tube is inserted into the trachea, and it is closed against the wall of the trachea by an inflatable cuff. The insertion of this tube involves risks that the anesthesiologist seeks to avoid or at least minimize. It is estimated that between one in 6,000 to one in 8,000 general anesthesia procedures result in death. There are of course many causes but of these it is estimated that about one third of them are caused by the intubation procedure.
The foremost obstacles encountered by the anesthesiologist include; the remoteness of the location where the tube is to be positioned, the consequent restriction of view as the tube is inserted, variations and anomalies in the anatomy of the patients, an uncomfortable and unnatural position for the anesthesiologist while holding the instrument, the potential need to change blades during the procedure, and the necessity for rapid intubation.
It should be noted that when the tube is inserted, the patient is asleep hyperoxygenated and then paralyzed for the procedure, and therefore not breathing. In addition, the ventilator is not yet in operation. This gives the anesthesiologist only about two minutes in which to intubate the patient, inflate the cuff, and start ventilation. If he is delayed because of unsuccessful attempts, he must stop, apply a ventilation mask to the patient, supply oxygen for a time through the mask, remove the mask, adjust medication if necessary, and then start over again. This delays the operation and extends the patient's time under anesthesia. This extension of time while under anesthesia may have very serious consequences, especially for elderly patients.
With the advent of endoscopic equipment and small cameras, instrumentation has been improved to the extent that it can enable viewing of the cords and larynx on a video screen thereby facilitating the intubation of the patient in a relatively quick and safe manner. However, conventional instrumentation may be further improved such that the laryngoscope is easier to use, thereby reducing the time involved for instance, to change blades or attach and detach peripheral components.
Endoscopes are now widely used in minimally invasive surgery. Endoscopes typically contain a light guiding system, usually in the form of fiber optic cables, in order to bring light to the surgical area. The light guiding system typically extends through the handle of the laryngoscope and through a guide tube located in the blade so as to position the light guiding system to illuminate the area ahead of the blade. Endoscopes also typically contain an image guiding system, for example in the form of a rigid rod lens system, arranged in the shaft of the endoscope. The image guiding system can also be configured as an ordered, flexible fiber optic bundle. The image guiding system is utilized to transmit reflected light from the area ahead of the blade to a camera. The camera, attached at the proximal end of the endoscope, usually contains a CCD (charge coupled device) sensor, in the form of a light-sensitive chip that converts the optical signals into electrical signals that are conveyed from the image-sensing camera module to a remotely located image processing system. The image guide typically extends from the distal end of the blade through the guide tube and then through the handle of the laryngoscope.
Typically, the combination light guiding system and image guiding system are permanently attached to the handle and are continuous, extending from the distal end of the blade, through the handle of the laryngoscope and to the camera for the image guiding system, and to the light source for the light guiding system. Therefore, the light guiding system and image guiding system extending from the handle of the laryngoscope for insertion into the guide tube of the blade typically comprise flexible coherent fiber optic bundles. However, when changing blades, the bundle must be carefully inserted or withdrawn from the opening of the guide tube at the proximal end of the blade. This may take an unacceptable amount time for the physician to thread the bundle into the tube if the blade must be changed in the middle of the intubation process.
The light and image guiding systems have typically been permanently attached to the handle to ensure the system will reliably transmit the illuminating light and reflected images. To utilize a detachably connectable light and image guiding system, the attachment means would have to rigidly hold the member in place such that the light and image guiding systems did not become misaligned. In addition, the attachment means must be easy and quick to operate, making it possible to perform the coupling procedure with as little close attention as possible, but nevertheless reliably. Provision must therefore be made for the coupling elements to be keyed to each other so that the coupling cannot be incorrectly joined and so that close attention by the operation is not required.
In addition, the flexible bundles may easily be damaged and will wear over time, degrading or rendering the system inoperable. As a visual inspection of the device often will not indicate whether the bundles are damaged, it is conceivable that a physician may obtain a damaged or malfunctioning laryngoscope not realizing that it is damaged. The time involved with determining that the instrument is malfunctioning, withdrawing it, finding another laryngoscope, and then intubating the patient may have severe adverse effects upon the patient under anesthesia.
Further, laryngoscopes, as with most medical equipment, must be sterilized after use. Because the light and image guiding systems are permanently attached to the handle, they are exposed to extremely high temperatures, which also cause wear and/or failure of the flexible bundles. Also, because the light and image guiding systems are subjected to the sterilization process with the handle and blades, the handle must be hermetically sealed which may greatly add to the cost in manufacturing such a device.
It is therefore desired to provide an improved video laryngoscope that is easy to use and will facilitate the quick removal and reattachment of a blade, the light guiding system and the image guiding system.
It is also desired to provide an improved video laryngoscope with a highly durable light guiding system and image guiding system.
It is further desired to provide an improved video laryngoscope that will reduce the costs associated with the manufacture of the laryngoscope.
It is also desired to provide an improved video laryngoscope having a coupling system that will reliably connect the laryngoscope handle with a light and image guiding attachment while requiring a minimal amount of attention from the user to attach or detach.